AMORTIZED SWIVEL COLUMN FOR OFFICE CHAIR

Abstract: Amortized swivel column for office chair of the type with two cylindrical bodies: a base column (2); a piston tube (1); a command rod (11) axially slideable within said tube to start a piston with inferior valve (114-115) that allows or prevents, depending on its position, the pouring of a fluid into an upper compartment (SS+S) between two chambers respectively upper (SS) and lower (S), to make possible the lengthening or shortening of the entire column in a condition of indifferent equilibrium, in which: said lower chamber of upper compartment (S) is connected directly to the bottom chamber of said lower compartment (I); in said upper (SS) and lower(S) chambers of said upper compartment (SS+S) and in said bottom chamber of said lower compartment (I) only compressed air (a) is found; in such a way that: when one wishes to very the height, one moves the said command rod (11) axially until said valve (114-115) puts said lower chamber (S) into communication (122-123) with said upper chamber (SS) in said upper compartment, allowing air to be drawn for compensation; when one sits down, with the height variation command blocked by means of moving the said command rod in a position in which said pouring is not possible, said piston tube (10-13-131) descends between the said base column pressing the base air chamber (1) and said lower chamber (S), and vice versa with an elastic return if there is no compression.

Description: 1 DESCRIPTION 2 3 AMORTIZED SWIVEL COLUMN FOR OFFICE CHAIR 4 Technical Field 5 This invention has for object an amortized swivel column for 6 office chair. 7 The chair using said column form is also object of the present 8 invention. 9 More particularly the invention regards an amortized swivel I 0 column for office chair with two cylindrical bodies: I I - a base column which lower base is connected or connectable to the 1 2 base of the chair; 1 3 - a piston tube that penetrates telescopically having a piston form, 1 4 amortized from the compressed air compression in a bottom chamber of 1 5 a lower compartment, within said column base, that exits more or less 1 6 from the column base with the upper extremity connected or 1 7 connectable under the seat of the chair; 1 8 - a command rod axially slideable within said tube to start a piston with 1 9 inferior valve that allows or prevents, depending on its position, the 0 pouring of a fluid into an upper compartment, between two chambers 1 respectively upper and lower, in order to allow the lengthening or 2 shortening of the entire column in a condition of indifferent 3 equilibrium. 4 Background Art 5 These types of column are well described in EP-0357592 and EP- 6 0462997 (IT-83355A/89), in which: 7 - said upper and lower chambers contain oil that by means of said valve 8 is poured over or under to vary the length (height of the seat); - said bottom chamber includes compressed air and acts from the amortizer of the seated. There exist other solutions of amortized swivel columns without oil, in which the amortizement is obtained by means of a helical spring and the variation of the height is obtained by means of a screw coupling between tube and column base. The second solution is of a mechanical type with all its limitations (lubrication necessity, necessity to rotate the seat to vary the height, danger in dirtying clothing with the oil underneath the column, etc.). The first solution is of dynamic-fluid type, extremely practical to use, therefore it is the one which is mainly used on the market. Notwithstanding this, it has some drawbacks: - weight and cost because of the presence of oil; - risk of leaking oil; - high operating cost for the necessity of making two separate sealing compartments, respectively: - an upper one containing the oil in two upper and lower chambers to vary the height and, - a lower one for the containing of the compressed air in order to have the amortizement of the seated. The risk in dirtying clothing however remains in both solutions. Aim of the present invention is to obviate to the above-mentioned drawbacks . This and other aims are reached as claimed by means of an amortized swivel column for office chair of the types with two cylindrical bodies: - a base column which lower base is connected or connectable to the base of the chair; - a piston tube that penetrates telescopically having a piston form piston, amortized from the compressed air compression in a bottom chamber of a lower compartment, within said column base, that exits more or less from the column base with the upper extremity connected or connectable under the seat of the chair; - a command rod axially slideable within said tube to start a piston with inferior valve that allows or prevents, depending on its position, the pouring of a fluid into an upper compartment, between two chambers respectively upper and lower, in order to allow the lengthening or the shortening of the entire column in a condition of indifferent equilibrium. characterized in that: • said lower chamber of said upper compartment is connected directly to said bottom chamber of said lower compartment, • in said upper and lower chambers of said upper compartment and in said bottom chamber of said lower compartment only compressed air is found; • in order that: - when one wishes to vary the height, one axially moves said command rod in order that said valve puts into communication said lower chamber with said upper chamber in said upper compartment allowing air to be drawn for compensation; - when one sits down, with the height variation command blocked by means of moving the said command rod in a position in which said pouring is not possible, said piston tube descends between the said base column pressing the base air chamber and said lower chamber, and visa versa with an elastic return if there is no compression. Advantageously the air will be dried to avoid seizures, rusting and condensation. In this way we obtain a much simpler column, lighter because only air is present, more simplified lacking an intermediate separating tube between two compartments, more reliable, without danger in dirtying clothing and therefore always clean. The sensible cost reduction (about 15%) finally provides a product qualitatively much more competitive on the market. These and other advantages will appear from the successive preferential solutions description of realization with the help the drawings included which particulars of execution are not to be considered limitative but only supplied as an example. Figure 1 is an axial section view of the column according to the present invention . Figure 2 is a partial view of the column concerning the lower compartment of the base column in a modified version in respect to the first. With reference to the figure it is disclosed that 1 indicates the piston tube with cylindrical metallic shell 10, while 2 indicates the base column with cylindrical metallic shell 20. Within the piston tube 1 slides the command rod 11 in plastic material, which lower extremity having a piston form with intermediate annular chamber valve 1 14 sealingly watertight from opposite gaskets 113, between a guide bush in plastic material 12 rigidly fixed in a position between the metallic shell 10 of the tube 1 by means of a lower filling in plastic material 14 holed axially 141 towards the lower compartment "I", in such a way that one has a communication between a lower "i" chamber under the piston with valve 115 and the bottom air chamber "I", that which will always supply an upward push of the command rod 1 1 , air being compressed and introduced downwardly on behalf the charging valve 25. in the bottom chamber "I". Obviously even the manifold valve support 12 has external sealing gaskets 121 to prevent the exit of compressed air; and has a couple of holes 122 and 123 spaced but comprised within the amplitude of the annular chamber of the piston tube 114. From the outside of said couple of holes and between these is anuarly fitted on the liner of the metallic cylindrical tube 10, a gasket ring 13 that with the respective annular gasket 131 acts from the tube piston 10. The upper extremity of the column 2 is closed by a ring 22 and before this a sealing flange 21. Between the sealing flange 21 and said piston gasket of the tube of 3 there is an upper annular chamber (SS) of the upper compartment "SS+S". Finally the tube extends downwards within the column and is guided by a lining 23 with holes 231 (finning) that acts from fixed partition to the external lining of the column 20, between the upper compartment "SS+S" and the lower compartment (I) but allows the passage of the air being drawn between these "SS-I" during its lowering or highering. The annular partition 23 can also extend downwardly until the bottom of the column 20 to form a stronger stop to the tube piston 13 and to better balance volumes between the bottom chamber and the lower chamber or better between the upper compartment "SS+S " and the lower compartment "I". In this way one has a softer movement. One will note that everywhere there is only air "a" that between the other the command rod 11 always pushes, thanks to "i" towards the top. For varying the height of the chair, it will therefore suffice to push the command rod 1 1 downwards, in this way one will have the valve (115) of fig.l which lowers and the air will be able to coflow from the lower chamber "S" to the upper chamber "SS", allowing the penetration of the tube enter the column 20 thanks also to the air passage between the bottom chamber "I" and the lower chamber "S". Once the stem 10 is let free, this, pushed from the pressure of the compressed air in the valve "i" raises and the valve 115 blocks the two passages 122-123 as illustrated in the figure. At this moment the column is blocked and cannot be varied in length . When one sits, the column will however shorten resiliently because the action of the column piston 1 13 intervenes that acts together with the bottom column 14-141 respectively the first against the stop 23 (lower chamber) and the second against the bottom of the column (bottom chamber) both communicant and therefore in continuous pressure equilibrium. Obviously the plastic material filling 14 could also lack to increase the volume of the bottom chamber "I". Alternatively the partition bush 23, as shown in fig. 2, can extend downwardly. In such a way taking the filling 14 and extending the stop bush 23 one obtains a further differentiation of the volume of the bottom chamber "I" whereupon one can therewith vary the elasticity, advantageous to avoid seizures or rustings of materials or formation of condensation inside the column, the internal introduced air will be dried.

Claims: 1 Claims 2 1. Amortized swivel column for office chair of the type with two 3 cylindrical bodies: 4 - a base column (2) which lower base is connected or connectable to the 5 base of the chair; 6 - a piston tube (1) that penetrates telescopically having a piston form, 7 amortized from the compressed air compression in a bottom chamber of 8 a lower compartment "I", within said column base (1), that exits more or 9 less from the column base (2) with the upper extremity connected or I 0 connectable under the seat of the chair; I I - one command rod (11) axially slideable within said tube to start a 1 2 piston with lower valve (1 14-115) that allows or prevents, depending on 1 3 its position, the pouring of a fluid into an upper compartment "SS+S" 1 4 between two chambers respectively upper "SS" and lower "S", in order 1 5 to allow the lengthening or shortening of the entire column in a 1 6 condition of indifferent equilibrium, 1 7 characterized in that: 1 8 • said lower chamber of said upper compartment "S" is connected 1 9 directly to said bottom chamber of said lower compartment "I", 0 • in said upper "SS" and lower "S" chambers of said upper compartment 1 "SS+S" and in said bottom chamber of said lower compartment "I" only 2 compressed air "a" is found; 3 • in order that: 4 - when one wishes to vary the height, one moves the said 5 command rod (1 1) axially in order that said valve (1 14-115) puts into 6 communication (122- 123) said lower chamber "S" with said upper 7 chamber "SS" in said upper compartment allowing air to be drawn for 8 compensation; - when one sits down, with the height variation command blocked by means of moving the said command rod in a position in which said pouring is not possible, said piston tube (10-13-131) descends between the said base column pressing the base air chamber (1) and said lower chamber "S", and visa versa with an elastic return if there is no compression. 2. Column according to claim 1, characterized in that it disposes of an axial communication (141 ) between said lower compartment "I" and valve "i" under said tube piston (115) and the respective compressed air always pushes said command rod (1 1) upwards. 3. Column according to claim 1 , characterized in that within the piston tube 1 slides a command rod (11) in plastic material, which lower extremity is of a valve piston form with intermediate annular chamber (114) watertight from opposite gaskets 1 13, within a guide bush in plastic material (12) fixed solidly in a position between a metallic shell (10) of said tube (1) by means of a lower filling in plastic material (14) holed axially (141) towards the lower compartment "I". 4. Tube according to preceding claims, characterized in that the air in the bottom chamber "I" compressed and introduced and adjusted inferiorly by means of the charging valve (25). 5. Column according to preceding claims, characterized in that said manifold supports valve (12) has external sealing gaskets (121) to prevent the exit of compressed air and has a couple of holes 122 and 123 spaced but comprised within the amplitude of an annular chamber of the valve piston (114). 6. Column according to the preceding claims, characterized in that, from the outside of said couple of holes (122-123) and between these is fitted in a ring fashion on the lining of the cylindrical metallic tube (10), a gasket ring (13) that with the respective annular gasket (131) acts from piston of the same tube (10) against an annular lower stop partition (23). 7. Column according to preceding claims, characterized in that the upper extremity of the column (2) is closed by a closing ring (22) and before this is a sealing flange (21). 8. Column according to preceding claims, characterized in that between said sealing flange (21) and said gasket with tube piston (13) there is an upper annular chamber (SS) of the upper compartment "SS+S", while the tube (1) extends downwardly within the column (2) and is guided from a lining as annular stop partition (23) with holings (231) that acts from partition, fixed to the external lining of the column (20), between the upper compartment "SS+S" and the lower compartment (I) but allows the passage of the air being drawn between these "SS-I" during its lowering or highering. 9. Column according to preceding claims, characterized in that said annular stop partition (23) extends downwardly until at the bottom of the column (20). 10. Column according to preceding claims, characterized in that the internal air of the same is dried. 1 1. Chair for office equipped with a column according to preceding claims.

Inventors: BERGAMASCO ALESSIO, BERGAMASCO, ALESSIO
Applicants: BERGAMASCO ALESSIO, LIFTER SRL, BERGAMASCO, ALESSIO, LIFTER S.R.L.
Application year: 1994
Main classification: A47C3
IPC codes: A47C3